People use respirators to avoid breathing certain substances (e.g., harmful gases, particulate matter, etc.), to avoid exhaling certain substances (e.g., droplets carrying germs), or both. The main body of a respirator typically fits over the mouth and nose of a user of the respirator. Accordingly, when the user exhales or inhales, air passes through the main body of the respirator, with the respirator then acting to filter the specific substances from the exhaled air or inhaled air.
The performance of the respirator depends, in part, on the fit between the respirator and the user's face. If the respirator is made of inflexible materials, then it may not readily conform to some of the complex contours of a face. As a result, flexible materials may be employed, for example at the perimeter of a respirator, to help provide a better fit. These flexible materials releasably engage skin. For example, a flexible polymeric material like rubber might be used for some portion of the main body of a re-usable respirator. In combination with straps that help pull the main body of the respirator toward a user's face, the rubber can help promote a gasket-like seal between the main body of the respirator and the face.
Some respirators, rather than being re-usable, are disposable. Such a respirator may be made from nonwoven materials, and might typically be used for a day or so. Often such respirators rely on the shape of the main body of the respirator, and the use of straps or strings attached to the main body of the respirator (and which wrap around the head of a user to help hold the respirator in place), to help conform the respirator to the face of a user.
Because neither of the aforementioned respirators adheres to the skin of a user, the position of either respirator may shift during use.
Various silicone materials, such as thermoplastic or thermoset materials in the form of a gel, film, foam, adhesive, and the like, have been identified as useful for releasably engaging skin. For example, silicone adhesives can exhibit desirable properties for gently adhering to skin. These same silicone adhesives can then be disengaged from the skin without painful pulling from, or injury to, skin with which the silicone adhesive is releasably engaged. Unfortunately, these same silicone adhesives typically do not satisfactorily adhere to other substrates. That is, such silicone adhesives, while satisfactorily adhering to, and releasing from, skin, typically do not adhere to other substrates such as a film, fibrous material (e.g., a woven or nonwoven), plastic, or other material.
What is needed is a material comprising silicone that is able to adhere to the surface of a substrate, such as a fibrous material typically used when constructing a respirator, while at the same time being capable of releasably engaging skin without causing injury or pain to the user of the substrate (e.g., a user of a respirator). Alternatively, this same material comprising silicone may be disposed between a silicone adhesive, such as a silicone gel adhesive or a silicone film adhesive, and a substrate such as a nonwoven, with the material comprising silicone joining the silicone adhesive to the substrate. In other words, the material comprising silicone facilitates attachment of the silicone adhesive to the substrate.